Valve-less mixing method and mixing device

Abstract

A fluidic device for mixing a reagent fluid with a fluid sample comprises a supply channel having a reagent inlet, a sample inlet and a first reagent storage, coupled to the supply channel; a mixer for mixing the reagent with the fluid sample, having a mixer inlet coupled to the supply channel at a position in between the sample inlet and the first reagent storage; In a first stage, when the reagent fluid is supplied in the reagent inlet, the reagent is provided in the supply channel and the first reagent storage, and such that the reagent is thereafter stationed in the supply channel and the first reagent storage until a fluid sample is provided in the sample inlet. When the fluid sample is supplied in the sample inlet, the supplied fluid sample and the stationed reagent flows into the mixer thereby mixing both fluids.

The invention claimed is: 
     
       1. A fluidic device for mixing a reagent fluid with a fluid sample, comprising:
 a supply channel having a reagent inlet for providing the reagent fluid in the supply channel and a sample inlet for providing the fluid sample in the supply channel; 
 a first reagent storage for storing the reagent fluid, coupled to the supply channel; 
 a mixer for mixing the reagent fluid with the fluid sample, having a mixer inlet and a mixer outlet, the mixer inlet coupled to the supply channel at a position in between the sample inlet and the first reagent storage; and 
 wherein the fluidic device is configured such that in a first stage, when the reagent fluid is supplied in the reagent inlet, the reagent fluid is provided in the supply channel and the first reagent storage, and such that the reagent fluid is thereafter stationed in the supply channel and the first reagent storage until the fluid sample is provided in the sample inlet; and 
 wherein the fluidic device is further configured such that in a second stage, when the fluid sample is supplied in the sample inlet, the supplied fluid sample and the stationed reagent fluid flows into the mixer thereby mixing both fluids. 
 
     
     
       2. The fluidic device according to  claim 1 ,
 wherein the first reagent storage is coupled to the supply channel via a first fluidic structure, 
 wherein the mixer is coupled to the supply channel via a second fluidic structure, 
 wherein, the first fluidic structure and the second fluidic structure are adapted such that a capillary pressure in the first fluidic structure is higher than a capillary pressure in the second fluidic structure such that, during the first stage, the reagent fluid flows into the first reagent storage and not into the mixer, and 
 wherein a capillary pressure in the first reagent storage is higher than a capillary pressure in the second fluidic structure such that the reagent fluid is stationed in the supply channel and the first reagent storage, after supplying the reagent fluid and before providing the fluid sample in the sample inlet; and 
 wherein the mixer and the first reagent storage are adapted such that a capillary pressure in the mixer is higher than the capillary pressure in the first reagent storage such that the supplied fluid sample and the stationed reagent fluid flow into the mixer. 
 
     
     
       3. The fluidic device according to  claim 1 , wherein the reagent inlet is adapted to accommodate a volume that is smaller than a volume of the first reagent storage and the supply channel combined. 
     
     
       4. The fluidic device according to  claim 2 ,
 wherein the first fluidic structure is a first fluidic channel forming the coupling between the first reagent storage and the supply channel, 
 wherein the second fluidic structure is a second fluidic channel forming the coupling between the mixer and the supply channel, and 
 wherein a width of the first fluidic channel and the second fluidic channel are adapted such that the capillary pressure in the first fluidic channel is higher than the capillary pressure in the second fluidic channel. 
 
     
     
       5. The fluidic device according to  claim 2 , wherein the first fluidic structure and/or the second fluidic structure comprises pillars which are in direct contact with the fluid sample, when present in the first fluidic structure and/or the second fluidic structure, and which are arranged such that the capillary pressure in the first fluidic structure is higher than the capillary pressure in the second fluidic structure. 
     
     
       6. The fluidic device according to  claim 1 , wherein the first reagent storage and the mixer each comprise fluidic channels having widths that are adapted such that a capillary pressure in the mixer is higher than a capillary pressure in the first reagent storage. 
     
     
       7. The fluidic device according to  claim 1 , wherein the first reagent storage and/or the mixer comprise pillars arranged such that a capillary pressure in the mixer is higher than a capillary pressure in the first reagent storage. 
     
     
       8. The fluidic device according to  claim 1 , wherein all fluidic components are closed. 
     
     
       9. The fluidic device according to  claim 1 , further comprising a glass cover positioned such that at least the supply channel, the first reagent storage, and the mixer are closed. 
     
     
       10. The fluidic device according to  claim 1 , wherein all components are fabricated in a silicon wafer. 
     
     
       11. The fluidic device according to  claim 1 , wherein the fluidic device is valve-less. 
     
     
       12. A multi-step assay device, comprising:
 the fluidic device according to  claim 1 ; 
 a fluidic channel coupled to the mixer outlet; 
 a second reagent storage coupled to the fluidic channel via a third fluidic structure; 
 a third reagent storage coupled to the fluidic channel via a fourth fluidic structure; 
 a first fluidic component coupled to the fluidic channel in between the third fluidic structure and the fourth fluidic structure; 
 a second fluidic component coupled to the first fluidic component via a fifth fluidic structure; and 
 a third fluidic component coupled to the second fluidic component via a sixth fluidic structure, 
 wherein the multi-step assay device is adapted such that: 
 a capillary pressure in the third fluidic structure is higher than a capillary pressure in the fifth fluidic structure; 
 the capillary pressure in the fifth fluidic structure is higher than a capillary pressure in the fourth fluidic structure; 
 the capillary pressure in the fourth fluidic structure is higher than a capillary pressure in the sixth fluidic structure; 
 a capillary pressure in the second fluidic component is higher than a capillary pressure of the second reagent storage; 
 a capillary pressure of third fluidic component is higher than a capillary pressure in the third reagent storage. 
 
     
     
       13. A multi-step assay device for DNA analysis, comprising a multi-step assay device according to  claim 12 , and wherein the first fluidic component is a PCR chamber. 
     
     
       14. A sensing system, comprising:
 the fluidic device according to  claim 1 ; 
 a sensor coupled to the mixer outlet and arranged for sensing an analyte in a mixed fluid sample exiting the mixer. 
 
     
     
       15. A method for mixing the reagent fluid with the fluid sample using the fluidic device according to  claim 1 , comprising:
 in a first stage: 
 providing the reagent fluid in the reagent inlet, wherein the provided reagent fluid is of a volume that is lower than a volume of the first reagent storage and the supply channel combined; thereafter allowing the reagent fluid to flow into the supply channel and the first reagent storage; and thereafter 
 in a second stage: 
 providing the fluid sample in the sample inlet. 
 
     
     
       16. A diagnostic device for diagnosing a status of an object or a patient,
 the diagnostic device comprising 
 the fluidic device according to  claim 1 ; and 
 a sensor coupled to the mixer outlet and arranged for sensing an analyte in a mixed fluid sample exiting the mixer, the sensor providing an output on which diagnosing can be based. 
 
     
     
       17. A diagnostic device for diagnosing a status of an object or a patient,
 the diagnostic device comprising 
 the multi-step assay device according to  claim 12 ; and 
 a sensor coupled to the mixer outlet and arranged for sensing an analyte in a mixed fluid sample exiting the mixer, the sensor providing an output on which diagnosing can be based.